Cation radicals and trication radicals of hexyl-substituted sexithiophene in solution

Hexyl-substituted sexithiophene was prepared by a coupling reaction of bromo-dihexyl-terthiophene. The hexyl-sexithiophelene was oxidized with ferric chloride in dichloromethane stepwise. The visible-near IR and ESR spectral change of the hexyl-sexithiophen during oxidation indicated that the first oxidation yielded cation radicals (polarons) and the successive second oxidation did not dications (bipolarons) but trication radicals. The cyclic voltammograms of the hexyl-sexithiophene showed three broad redox peaks and suggest several oxidation processes.